Method of making ball centers



E. HAZELL 2, METHOD OF MAKING BALL CENTER Filed- Feb. 7. 11939 INVENTOR.

ATTORNEYS Patented July 18, 1944 ivmcruonor MAKING BALL CENTERS Eardleyto United Hazell, North Kingstown,

States Rubber Company, N. Y., a corporation of New Jersey R. I assigno'rNew York,

Application February'l, 1939, Serial Nmzsaosc 4 Claims.

This invention relates to a method of-making a ball center, and moreparticularly a golf ball center.

Practically all modern are now made with a tense winding of rubberthread around a mobile or liquid center, since this construction hasbeen found to give a maximum of distance and other desirablecharacteristics. In the making of such centers it is necessary toconfine the liquid or mobile filling material within an outer flexibleor resilient envelope before the thread winding operation can beinitiated. In some cases, balls have been made by utilizing an outerenvelope of rubber within which a mobile filling material is located,vbut due to the mobility of the filler element, the thread windingoperation cannot readily be started directly on a winding machine, andinstead the winding at beginning of the operation has been manuallyperformed, using a broad rubber tape, and after sufiicient windings ofthis better grade golf balls had been placed on the center it becamefirm enough to start the machine winding. However,

the center is objectionthis method of winding able because at bestitcannot produce a ball with a symmetrically disposed and round-ed center,and the earlier windings cannot be put on at the desired tension, sothat the finished ball has windings of different tensions at differentdistances from its center. the common procedure has been to fill arubber envelope with a mobile material and then freeze the assembly sothat winding of the thread could be directly started by machine on thefrozen center. Still another method has been to first freeze in a moldthe mobile filling material and then surround it by a rubber envelope.

One method of making the rubber envelopes has been to provide a smallthin sac of rubber made by a dipping'process from a rubber cement orlatex, the sac beingprovided with a filling neck. After forming andvulcanizing such a sac it is filled with the desired mobile filler, theneck tied oii" with rubber thread, and the excess portion of the neckcut ofi. This operation is a messy one, andit produces a center which isirregular by reason of theremaining portion of the neck and the threadtying it ofi.

Another method has been to form hemispherical molded halves or cups ofrubber which are semi-cured or completely cured, and then united as byrubber cement. This envelope is then filled with the desired mobilematerial by means of. a hypodermic needle. 7

All of these methodslhave objections by reason To obviate this objectionan apparatus illustrating an of cost, handling of the mobile material,undue amount of hand labor, and: other objections. Also, in one of thabovemethodsit has been necessary to use and vulcanizing theflatter, and:a second one other play 'ballcenters, and'alsoan improved article.

Another object is to: avoid one orboth freezing operations.

Another object. is to. providei'a ball center with a filling of materialor materials which are normally solid or immobile, but which after.incorporating in the center may readily'be converted into a mobile or.liquid form.

Other objects will. appear from description. and drawing inz whichlatter:

Figure l is a diagrammatic sectional view or initialstepofi the method;

Figure 2 is-asimilar: sectional view showing a second step;

Figure, 3 is 'a-se'ctional- View of a" completed. pill of fillingmaterial";

Figure 4' is a sectional view illustrating the. stepof placing arubber-like envelope a'round thepill;-

and

center with a liquid or mobile filling.

in connection with globule 3 of solid alkali hydroxide, such-as sodiumhydroxide, is" formed and of powdered hydrous silica.

of sodium hydroxide,

removed appearing in section as shown in Figure- 3. This 'pill orfilling is'then enclosed in two hemispherical halves i of an outerenvelope: which may be madeofirubber. Thesehalves'may be made of arubberco'mpound which hasb'een' given a slight set cure, and thetwo-halves are- -then further-cured and united around thecentral" pillby heatand pressure in; a mold with=o1-yvithe out the aid of cementforuniting the halves; For

example, the rubber'stock may be socompounded that the desired degree offinal vulcanization in;

two freezing operations, one before placing, the" filling material initsenvelopethe detailed- Figure 5 is a sectional view showin acompleteplaced in themol'd b'y' bedding it approximately centrally in acharge '4 The mold is then closed as shown in Figure 2 to compress thehydrous silica in solid form around the globule the a completedfillingwhen reached a-hard,.-glassy state, and it may, readily be ground ftoformfiafjfairly freel flowing powden This material maybe molded as sucharound the globule of alkali'hydroxide, but the molded pill is somewhatbrittle, and it is therefore preferred to' add a binding material to thehydrous'sili'ca, such as titanium dioxide, zinc oxide, or glue. I 1 HAfter molding, the alkali hydroxide will begin ordinary temperatures,and then react with the to Withdraw water from the hydrous silica atsilica to form sodium silicate; and'the'rfore, the pill must be coveredat once, if prepared as above described. However, in order to enablestorage of the pills until-used; they may be kept at a low temperature'approximately the freezing point of water. which will retard action bythe alkali hydroxide. :As' an alternative, the-:globule of sodiumhydroxide may begivenia thin' coating of paraffin wax or:othersuitablematerial, which will also preserve the completed moldedpill from any reaction between its ingredients until desired. Uponmolding the hemisphericalhalves of the rubber or otherenvelope'arollndthe completed pill, the heat of the molding and curingoperation will cause the action of the alkali hydroxide to begin, or inthe case where the central globule is coated with parafiin wax it willsoftenithelatter sufficientlyforthe reaction to begin. Upon withdrawalof water from the hydrous silica the alkali hydroxide becomes'liquefiedand reacts with the silica to produce an alkali silicate'and water. Thequantity of water present .in the hydrous silica is sufficient to.liquefyor. mobilize the entire contents of'the rubber envelope. e, I.It is not essential that the. rubber hemi-spheres be set vulcanized, asthey may be merely :Inolded under heat from unvulcanizable; stock andused in an unvulcanized condition. Alsoyinstead of giving therubberhemi-spheres only aset cure during their molding they may be vulcaniz dto the desired ,finished :state andthejwo-hemispheres then' unitedaround the=centralpil1of filling material by means of a rubber cement,such as. a cold curing .one. iAlso, in place of. rubber there may be:used any; suita'ble synthetic or substitute rubberor,othenmaterialghaving suitable properties, such as thetrade materialknown as Neoprene, which is a polymer of chloro-Z- butadiene 1,3. Thecovering may also be applied byadipping operation.

If the pill of fillingingredients; is surrounded by an envelope ofpreviously cured rubber. as just described, it is obvious thatthecentermay be used at once for. applying a, tense winding of rubber thread,thus avoidingall freezing-steps of the priorart. In such case, .Where noheat whatever is used in applying the rubber envelope, the form ofcentral globuleof alkalihydroxide which is coated withparafiin'waxpcannot be employed, unless-heatis later applied ;-to.- thewound center to soften the wax andstart thereaction between the fillingingredients. However, where there isus'ed the. globule which 'does notembody the coating of paraflin wax, it will almost immediately starttoliquefy at ordinary temperatures as before pointed out, and therefore,the covered center can be woun'dfand merely allowed to stand EXAMPLE #lTitanium dioxide, silica gel, and

NaOH

I Dry I Wet Silieagel 277 0 100. 0 Titanium dioxide 75.0 75.0 NaOH(solid pellet); 9.6 9.6

EXAMPLE #2 This example is identical with Example #1 except thatparts ofzinc oxide are used in place of the 75 parts of titanium dioxide.

EXAMPLE #3.Silica. gel, glue, and NaOH Glue (powdered) "It is notessential to the invention that the filling material for the center becomposed of hydrous silica and an alkali hydroxide, as any othersuitable solid materials which are not injurious to rubber and notdangerous to handle may be used. Y All that is required is that amaterial or materials be employed embodying water or other liquid ortheelements thereof in sufficient amount to ultimately liquefy or rendermobile the filling of the center when the liquid is liberated, or thatthe materials, interact to produce a mobile or liquid resultant.

EXAMPLE #4 As the filling material there may be employed an equivalentof sodium sulfate (decahydrate) and an equivalent of calcium nitrate(tetrahydrate), which materials will lose water and react when heated toproduce an equivalent of calcium sulfate in precipitated form, 2equivalents of barium chloride (dihydrate) for a short time in -order topermit thealka'li 75' sodium nitrate and 14 of water.

EXAMPLE #5 A further combination is an equivalent of V I v and anequivalent of sodium carbonate (decahydrate), which materials will reactunder heat to produce an equivalent of barium carbonate in precipitatedform, 2 equivalents of sodium chloride and 12 of water.

EXAMPLE #6 A still further combination is an equivalent of disodiumphosphate (dodecahydrate) and an equivalent of barium chloride(dihydrate), which ingredients will react under heat to produce anequivalent of barium diphosphate in precipitated form, 2 equivalents ofsodium chloride and 14 of water.

EXAMPLE #7 Still another combination is an equivalent of sodium sulfate(decahydrate) and an equivalent of barium nitrate, which ingredientswill react under heat to produce an equivalent of barium sulfate inprecipitated form, 2 equivalents of sodium nitrate and 10 of water.

It is also pointed out that a large variety of liquids, such as alcoholsand acids such as acetic, will associate with salts. For example,calcium nitrate may contain ethyl alcohol of crystallization. Therefore,the invention is not limited to water for obtaining liquefaction ormobilization in the finished center.

In all forms of the invention the filling material of the centerultimately becomes a liquid or mobile body containing matter in solutionor suspension or both.

t will be seen that by the invention a center for golf balls or similargame balls has been provided which at the time of manufacture contains afilling of materials which are solid at ordinary temperatures, but whichunder determinate time and temperature conditions may be reduced to aliquid or mobile condition, which is retained at ordinary temperatures.Therefore, by the present method the centers may be made and at least apartial liquefaction of the filling material produced during the moldingand/or vulcanization of a rubber or similar envelope around the solidfilling material. The liquefaction will then continue at ordinarytemperatures until the entire filling of the center has been reduced toa mobile condition. If such centers are to be wound after the fillinghas become partly or wholly liquid, it is of course necessary or atleast desirable to freeze them before initiating the winding operation.However, it will be seen that by the invention the preliminary freezingof the material during the making of the center has been entirelyavoided. On the other hand, if a rubber envelope of the state ofvulcanization desired in the finished article is initially used forcovering the solid comprises, forming filling material, it is possibleto directly machine wind the thread on such a center, thus avoiding anyof the prior art freezing steps. In such case, the filling material inthe center upon standing for a short time at ordinary temperatures willliquefy without elevation of temperature, but as before pointed out, insuch case a central globule of alkali hydroxide which is not coveredwith water impermeable material should be used.

It is obvious that numerous modifications may be made in the method andin the materials used, and it is not desired to limit the inventionotherwise than as set forth in the appended claims.

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

1. The method of making a ball center which comprises, molding to shapea pill from a, partially dehydrated substantially dry to the touchgranulated silica gel and an alkali hydroxide, enclosing the pill in anenvelope of rubber-like material, and subjecting the assembly to timeand temperature conditions sufiicient to reduce the pill to a mobilebody including alkali silicate and water.

2. The method of making a ball center which comprises, molding partiallydehydrated substantially dry to the touch granulated silica gel around asolid center of alkali hydroxide to form a pill, enclosing the pill inan envelope of rubberlike material, and subjecting the assembly to timeand temperature conditions sufficient to reduce the pill to a mobilebody including alkali silicate and water.

3. The method of making a ball center which a small center of solidalkali hydroxide, coating the same with water impermeable but heatliquefiable material, molding granulated hydrous but substantially dryto the touch silica gel around the coated small center to form a pill,enclosing the pill in an envelope of rubber, and curing said envelopeunder heat and pressure to thereby liquefy said coating and permitreaction of said silica gel and alkali hydroxide to form a mobile body.

4. The method of making a ball center which comprises, forming a spherecontaining a quantity of a partially dehydrated substantially dry to thetouch granulated silica gel and a separate quantity of an alkalihydroxide, and inclosing the sphere in an envelope of resilientmaterial, to thereby provide a ball center having an inclosed spherewhich when subjected to proper time and temperature conditions will forma mobile body including alkali silicate and water.

EARDLEY HAZELL.

